This invention pertains to pressure washing machines and particularly to pressure washing machines supported on wheels.
Many portable pressure washing machines are mounted on wheels and include an internal combustion engine and an associated pump mounted on a frame. The operation of the engine creates substantial vibration in the frame of the pressure washer and this vibration can be translated into movement of the pressure washing machine along the surface on which it rests. This is highly undesirable. In order to reduce such undesirable movement of the machine when it is running, it has been usual practice to fabricate the frames for the machines from heavy steel plate, with the frame components welded together, and with stiffening ribs to rigidify the frame to cause machine vibration to be transmitted from the engine to the wheels where the vibrations can be absorbed sufficiently to allow the machine to remain at rest when the motor is running.
Developing demand for lighter weight portable pressure washing machines has not been satisfactorily met because the fabrication of pressure washer frames from aluminum, thinner gauge mild steel or stainless steel, or from other lighter weight materials does not result in the transmission of sufficient engine vibration to the wheels such that pressure washers with frames fabricated from lighter weight materials tend to vibrate excessively and “walk” along the surface on which they rest.
One manufacturer of pressure washing machines employs rubber vibration isolators mounted between the internal combustion engine and the machine frame. This structure has not been found to sufficiently dampen the vibrations to prevent the undesired movement of the pressure washing machine when its engine is running.
A need exists for a vibration absorbing structure of low cost and low complexity which will permit pressure washing machines to be fabricated with frames of lightweight materials without the need to use brakes or wheel blocks to keep the pressure washing machine in place when in operation.